When textiles, such as clothing, linens and the like, are laundered, it is typically desired that wrinkles be eliminated or minimized after the cleaning and drying process. Mechanical wrinkle reduction techniques, such as heat and pressure (for example, ironing), have been used but can be time consuming and inconvenient.
Known attempts to reduce wrinkles by means of chemical ingredients in the wash include the use of zwitterionic surfactants, aminosilicones, curable aminosilicones, cellulase enzymes and alkyl amides. However, each of these ingredients have one or more drawbacks. For example, zwitterionic surfactants are believed to work best in cold water. Aminosilicones can cause yellowing and can be difficult to formulate. Curable aminosilicones require the heat of an iron to reduce wrinkles. Cellulase enzymes generally require several wash cycles before anti-wrinkle benefits become noticeable. Alkyl amides are not very effective relative to other wrinkle reducing agents.
Therefore, there is a need for an effective and efficient means for eliminating or reducing wrinkles in textiles. To be effective and efficient, the ingredient should preferably work across a broad range of water temperatures, not require the use of an iron, have little to no discoloration effect on the laundered item and/or provide a noticeable wrinkle reducing benefit after relatively few wash cycles.
The present application relates to the inclusion of one or more wrinkle reducing ingredients in a laundry detergent product. The benefits are delivered to the laundered item during the cleaning step and, therefore, reduces the need for further wrinkle reducing steps when the items are taken from the dryer or after hang drying.
The ingredients that facilitate the benefit of wrinkle reduction are believed to lubricate fiber surfaces. By lubricating the fiber surfaces of garments, for example, the fibers slide more easily relative to each other and are less likely to entangle, resulting in less wrinkles. The preferred fiber lubricants disclosed herein have been shown to noticeably reduce the number of wrinkles. The preferred embodiments also overcome one or more of the above noted disadvantages of prior wrinkle reducing agents or methods.
While it is known that lubricants can be used to reduce wrinkles in textiles, it was surprisingly found that these materials work from a main wash detergent. More particularly, main wash detergents are highly diluted and are subject to one or more rinse cycles. Such high dilution and rinsing would be expected to diminish or eliminate the desired wrinkle reduction effect of the lubricant.
Several molecules have been identified for wrinkle reduction benefits when included in known liquid detergent formulations. Using the American Association of Textile Chemists and Colorists (AATCC) method #124 (described in greater detail, below), the following molecular classes were found to reduce the number of wrinkles on test cloths: polyalkyleneoxide modified polydimethylsiloxane; linear aminopolydimethylsiloxane polyalkyleneoxide copolymers; sulfated/sulfonated vegetable oils, such as sulfated canola oil or sulfated castor oil; high molecular weight polyacrylamides; betaine siloxane copolymers; and alkylactam siloxane coplymers. Of the foregoing, a most preferred wrinkle reducing agent is a polyalkyleneoxide modified polydimethylsiloxane, sold under the name Silwet L-7622, available from Witco, Greenwich, Conn. Other most preferred wrinkle reducing agents are sulfated canola oil and/or castor oil available from Freedom Chemical Co., Charlotte, N.C.
One or more of the molecules/compounds from the above-identified classes are preferably included in known detergent formulations in an effective amount sufficing to reduce the occurrence of wrinkles as compared to clothing laundered and dried in a similar manner with a detergent formulation that excludes the wrinkle reducing agents. An effective amount of the wrinkle reducing ingredient is preferably from about 0.1 wt % to about 5 wt % and most preferably from about 0.3 wt % to about 1.5 wt %. However, sulfated/sulfonated vegetable oils can be used at even higher levels, such as from 0.1 wt % to 10 wt % due to their ease of formulation and relatively low cost. Suitable liquid detergent formulations are described, for example, in U.S. Pat. Nos.: 4,261,868; 4,322,308; 4,959,179; 5,089,163; 5,147,576; and 5,205,957, all of which are incorporated herein by reference.
An additional advantage of the above-identified wrinkle reducing ingredients is that the molecules/compounds do not have a net positive charge in a neutral or alkaline medium, i.e. a medium having a pH greater than or equal to about 6.5. Lack of a net positive charge makes their inclusion in liquid detergents containing anionic surfactants much easier. More specifically, they are less likely to precipitate with negatively charged surfactants.
A further advantage is the likelihood of xe2x80x9cyellowingxe2x80x9d fabrics with the above wrinkle reducing molecules is less than with amine-containing ingredients. In addition, some of the above wrinkle reducing ingredients, such as sulfated vegetable oils, are relatively inexpensive.
Wrinkle reduction was measured by using the American Association of Textile Chemists and Colorists"" (AATCC) method #124, Appearance of Fabrics after Repeated Home Laundering. In this method, four cloth types (silk, rayon, cotton, and linen) are washed, dried and stored in a well defined way. The dried cloths are then evaluated for wrinkle content by comparison with wrinkle smoothness replicas which can be purchased from AATCC. Factors such as the light used, the angle of the cloths and replicas to the light, and the background are carefully controlled and described in the method. There are six replicas with values of 1, 2, 3, 3.5, 4, and 5 with 5 being perfectly smooth and 1 being very wrinkled. Three trained observers are asked to give a value of 1-5, to the nearest 0.5 unit, to each cloth based on which replica it most closely resembles. The results are totaled and averaged over the three observers for each cloth type. According to the method, a difference of greater than 0.17 between the results for two products indicates there is a significant difference at the 95% confidence level. A difference of greater than or equal to 0.25 indicates a significant difference at the 99% confidence level.